Remarkable substituent effects on the photophysics of Pt(4′-X-trpy)Cl+ systems (trpy = 2,2′; 6′,2″-terpyridine)

Switching between Ligand‐to‐Ligand Charge‐Transfer, Intraligand Charge‐Transfer, and Metal‐to‐Ligand Charge‐Transfer Excited States in Platinum(II) Terpyridyl Acetylide Complexes Induced by pH Change and Metal Ions

“…We have tentatively ascribed this band to an ILCT transition from the p orbital of the amino-substituted phenyl group to the p* orbital of the metal-bound terpyridyl moiety, probably mixed with some dp(Pt)!p*A C H T U N G T R E N N U N G (terpy) MLCT contribution. [39] This assignment was made on the following grounds. First, it has been established that the absorption and fluorescence spectra of the ligand, 4'-[4-N-A C H T U N G T R E N N U N G (CH 3 ) 2 -C 6 H 4 ]-2,2':6',2''-terpyridine (4'-aminophenyl-terpy), are observed at much longer wavelengths compared with those of 4'-phenyl-2,2':6',2''-terpyridine (4'-phenyl-terpy), which has no amino substituent at the 4-position of the phenyl group.…”

“…[38] This substituted terpyridine has served as a ligand in the assembly of Pt II complexes that display a low-lying ILCT excited state in which the aminosubstituted phenyl acts as the electron donor and the metalbound terpyridyl as the acceptor. [39] We postulate that platinum(II) terpyridyl acetylide complexes, which bear amino group(s) or azacrown group(s) on both their terpyridyl and acetylide ligands, might exhibit lowest-lying excited states having either ILCT or LLCT character. Furthermore, these excited states might be interchanged by a change of solvent or pH, or by the introduction of metal ions, thereby yielding a variety of interesting photophysical properties.…”

Photoluminescence Emission and Photoinduced Hydrogen Production Driven by PtII Pyridyl Complexes Anchored onto Mesoporous Silica

“…[13] The situation is different for [PtA C H T U N G T R E N N U N G (tpy)]-MCM-48, for which strong luminescence at room temperature is observed near 530 nm due to 3 LC and/or 3 MLCT transitions (Figure 3 A). It is likely that the rigid matrix within the mesoporous silica channel efficiently blocks the deactivation processes through molecular distortion.…”

Theoretical study of the electronic structures and spectroscopic properties of [(4′-XC ≡ Ctrpy)PtCl]+ (trpy = 2,2′:6′,2″-terpyridine; X = H, Me and Ph)

“…McMillin et al investigated the photophysical impact of 4′-substituted terpyridyl ligands in various square planar Pt(Ⅱ) complexes. They demonstrated that the substitution of the 4′-position of the terpyridyl unit can render Pt(Ⅱ) terpyridyl chloro complexes luminescent in solution, even if the majority of them display stronger emission in the solid state [37,38,[40][41][42][43][44][45][46][47][48] . Strategic functionalization in the 4′-position can lower the energy of the MLCT (metal to ligand charge transfer) excited state, thereby attenuating deactivation pathways from ligand field excited state.…”